Rf receiver

ABSTRACT

A device includes, in part, an antenna adapted to receive an RF signal that includes modulated data, a splitter/coupler adapted to split the received RF signal, a receiver adapted to demodulate the data from a first portion of the RF signal, and a power recovery unit adapted to convert to a DC power a second portion of the RF signal. The splitter/coupler is optionally adjustable to split the RF signal in accordance with a value that may be representative of a number of factors, such as the target data rate, the DC power requirement of the device, and the like. The device optionally includes a switch and/or a power combiner adapted to deliver all the received RF power to the receiver depending on any number of operation conditions of the device or the device&#39;s distance from an RF transmitting device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of application Ser.No. 14/078,489, filed Nov. 12, 2013, entitled “Smart RF Lensing:Efficient, Dynamic And Mobile Wireless Power Transfer” which claimsbenefit under 35 §U.S.C 119(e) of U.S. Provisional Patent ApplicationNo. 61/724,638, filed Nov. 9, 2012, entitled “Smart RF Lensing:Efficient, Dynamic And Mobile Wireless Power Transfer”, the contents ofwhich are incorporated herein by reference in its entirety.

The present application claims benefit under 35 §U.S.C 119(e) of U.S.Provisional Patent Application No. 62/222,106, filed Sep. 22, 2015,entitled “Smart RF Lensing: Efficient, Dynamic And Mobile Wireless PowerTransfer”, the content of which is incorporated herein by reference inits entirety.

The present application is related to the following US applications:

-   -   application Ser. No. 14/552,249, filed Nov. 24, 2014, entitled        “Active CMOS Recovery Units For Wireless Power Transmission”;    -   application Ser. No. 14/552,414, filed Nov. 24, 2014, entitled        “Generator Unit For Wireless Power Transfer”; and    -   application Ser. No. 14/830,692, filed Aug. 19, 2015, entitled        “Wireless Power Transfer”;        the contents of all of which applications are incorporated        herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to wireless communication, and moreparticularly to wireless power and data transfer.

BACKGROUND OF THE INVENTION

Electrical energy used in powering electronic devices comespredominantly from wired sources. Conventional wireless power transferrelies on magnetic inductive effect between two coils placed in closeproximity of one another. To increase its efficiency, the coil size isselected to be less than the wavelength of the radiated electromagneticwave. The transferred power diminishes strongly as the distance betweenthe source and the charging device is increased.

BRIEF SUMMARY OF THE INVENTION

An RF lens, in accordance with one embodiment of the present invention,includes, in part, a multitude of radiators adapted to radiateelectromagnetic waves to power a device positioned away from the RFlens. Each of the multitude of radiators operates at the same frequency.The phase of the electromagnetic wave radiated by each of the multitudeof radiators is selected to be representative of the distance betweenthat radiator and the device.

In one embodiment, the multitude of radiators are formed in an array. Inone embodiment, the array is a one-dimensional array. In anotherembodiment, the array is a two-dimensional array. In one embodiment, theamplitudes of the electromagnetic waves radiated by the radiators isvariable. In one embodiment, each of the multitude of radiatorsincludes, in part, a variable delay element, a control circuit adaptedto lock the phase or frequency of the electromagnetic wave radiated bythat radiator to the phase or frequency of a reference signal, anamplifier, and an antenna.

In one embodiment, the multitude of radiators are formed in a firstradiator tile adapted to receive a second radiator tile having disposedtherein another multitude of radiators. In one embodiment, the RF lensis further adapted to track a position of the device. In one embodiment,each of a first subset of the radiators includes a circuit for receivingan electromagnetic wave transmitted by the device thus enabling the RFlens to determine the position of the device in accordance with thephases of the electromagnetic wave received by the first subset of theradiators.

In one embodiment, each of at least a first subset of the radiatorsincludes a circuit for receiving an electromagnetic wave transmitted bythe device thereby enabling the RF lens to determine a position of thedevice in accordance with a travel time of the electromagnetic wave fromthe device to each of the first subset of the radiators and a traveltime of a response electromagnetic wave transmitted from the RF lens tothe device. In one embodiment, the RF lens is formed in a semiconductorsubstrate.

A method of wirelessly powering a device, in accordance with oneembodiment of the present invention, includes, in part, transmitting amultitude of electromagnetic waves having the same frequency from amultitude of radiators to the device, selecting a phase of each of themultitude of radiators in accordance with a distance between thatradiator and the device, and charging the device using theelectromagnetic waves received by the device.

In one embodiment, the method further includes, in part, forming theradiators in an array. In one embodiment, the radiators are formed in aone-dimensional array. In another embodiment, the radiators are formedin a two-dimensional array. In one embodiment, the method furtherincludes, in part, varying the amplitude of the electromagnetic waveradiated by each of the radiators.

In one embodiment, each radiators includes, in part, a variable delayelement, a controlled locked circuit adapted to lock the phase or thefrequency of the electromagnetic wave radiated by the radiator to thephase or frequency of a reference signal, an amplifier, and an antenna.In one embodiment, the radiators are formed in a first radiator tileadapted to receive a second radiator tile having disposed thereinanother multitude of radiators.

In one embodiment, the method further includes, in part, tracking theposition of the device. In one embodiment, the method further includes,in part, determining the position of the device in accordance withrelative phases of an electromagnetic wave transmitted by the device andreceived by each of at least a subset of the radiators. In oneembodiment, the method further includes, in part, determining theposition of the device in accordance with a travel time of anelectromagnetic wave transmitted by the device and received by each ofat least a subset of the radiators, and further in accordance with atravel time of a response electromagnetic wave transmitted from the RFlens to the device. In one embodiment, the method further includes, inpart, forming the RF lens in a semiconductor substrate.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a splitter/coupler adapted to split thereceived RF signal into first and second portions, a receiver adapted todemodulate the data from the first portion of the received RF signal,and a power recovery unit adapted to convert the second portion of theRF signal to a DC power to power the device. In one embodiment, thesplitter/coupler is an adjustable splitter/coupler

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a receiver adapted to demodulate the data froma first portion of the RF signal, a power recovery unit adapted toconvert a second portion of the RF signal to a DC power to power thedevice, and a controller adapted to receive the RF signal from theantenna and generate the first and second portions of the RF signal inaccordance with impedance values of the receiver and the power recoveryunit.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a switch adapted to receive the RF signal fromthe antenna, a power recovery unit adapted to convert the RF signal to aDC power to power the device when the switch is in a first position, anda receiver adapted to demodulate the data from the received RF signalwhen the switch is in a second position.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a splitter/coupler adapted to split thereceived RF signal into first and second portions, a switch adapted toreceive the second portion of the RF signal from the splitter/coupler, apower recovery unit adapted to convert the second portion of the RFsignal to a DC power to power the device when the switch is in a firstposition, and a power combiner adapted to receive the first portion ofthe RF signal from the splitter/coupler and further to receive thesecond portion of the RF signal when the switch is in a second position,and a receiver adapted to demodulate the data from an output signal ofthe power combiner. In one embodiment, the device further includes acontroller adapted to cause the switch to be in the first position whena power of the received RF signal is less than a first threshold value.In one embodiment, the device further includes a controller adapted tocause the switch to be in the first position when the device indicatesthat its DC power exceeds a second threshold value.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a switch adapted to receive the RF signal fromthe antenna, a power combiner coupled to a first output terminal of theswitch to receive the RF signal when the switch is in a first position,a splitter/coupler coupled to a second output terminal of the switch toreceive the RF signal, when the switch is in a second position, to splitthe RF signal into a first portion and a second portion and deliver thefirst portion of the RF signal to the power combiner, a power recoveryunit adapted to convert the first portion of the RF signal to a DC powerto charge the device when the switch is in the second position, and areceiver adapted to demodulate the data from an output signal of thepower combiner. In one embodiment, the device further includes, in part,a controller adapted to cause the switch to be in the first positionwhen a power of the received RF signal is less than a threshold value.In yet another embodiment, the device further includes a controlleradapted to cause the switch to be in the first position when the deviceindicates that its DC power exceeds a threshold value.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a controller, an adjustable splitter/coupleradapted to split the received RF signal into first and second portionsin accordance with a value the adjustable splitter/coupler receives fromthe controller, a receiver adapted to demodulate the data from the firstportion of the RF signal, and a power recovery unit adapted to convertthe second portion of the RF signal to a DC power to charge the device.In one embodiment, the value supplied by the controller is defined by atarget data rate of the device. In another embodiment, the valuesupplied by the controller is defined by a DC power requirement of thedevice.

A method, in accordance with one embodiment of the present invention,includes, in part, receiving an RF signal that includes modulated data,splitting the received RF signal to first and second portions,demodulating the data from the first portion of the RF signal, andconverting the second portion of the RF signal to a DC power.

A method, in accordance with one embodiment of the present invention,includes, in part, receiving an RF signal that includes modulated data,demodulating the data from a first portion of the received RF signal viaa receiver, converting a second portion of the RF signal to a DC powervia a power recovery unit, and generating the first and second portionsof the RF signal in accordance with impedance values of the receiver andthe power recovery unit.

A method, in accordance with one embodiment of the present invention,includes, in part, receiving an RF signal that includes modulated data,converting the RF signal to a DC power when a switch is in a firstposition, and demodulating the data from the received RF signal when theswitch is in a second position.

A method, in accordance with one embodiment of the present invention,includes, in part, receiving an RF signal that includes modulated data,demodulating the data using either a first portion of the RF signal orthe RF signal, and converting a second portion of the RF signal to a DCpower when the first portion of the RF signal is used for demodulatingthe data. In one embodiment, the data is modulated using the RF signalwhen a power of the received RF signal is less than a first thresholdvalue. In one embodiment, the data is demodulated using the RF signalwhen an indication is received that a battery charge exceeds a thresholdvalue.

A device, in accordance with one embodiment of the present invention,includes, in part, an antenna adapted to receive an RF signal thatincludes modulated data, a controller, an adjustable splitter/coupleradapted to split the received RF signal into first and second portionsin accordance with a value the adjustable splitter/coupler receives fromthe controller, a receiver adapted to demodulate the data from the firstportion of the RF signal, and a power recovery unit adapted to convertthe second portion of the RF signal to a DC power to charge the device.In one embodiment, the value supplied by the controller is defined by atarget data rate of the device. In another embodiment, the valuesupplied by the controller is defined by a DC power requirement of thedevice.

A method, in accordance with one embodiment of the present invention,includes, in part, receiving an RF signal, splitting the received RFsignal to first and second portions in accordance with a received value,demodulating the data from the first portion of the RF signal, andconverting the second portion of the RF signal to a DC power. In oneembodiment, the value is defined by a target data rate. In oneembodiment, the value is defined by a DC power requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a one-dimensional array of radiators forming an RF lens, inaccordance with one embodiment of the present invention.

FIG. 2 is a side view of the RF lens of FIG. 1 wirelessly deliveringpower to a device at a first location, in accordance with one exemplaryembodiment of the present invention.

FIG. 3 is a side view of the RF lens of FIG. 1 wirelessly deliveringpower to a device at a second location, in accordance with one exemplaryembodiment of the present invention.

FIG. 4 is a side view of the RF lens of FIG. 1 wirelessly deliveringpower to a device at a third location, in accordance with one exemplaryembodiment of the present invention.

FIG. 5 shows a two-dimensional array of radiators forming an RF lens, inaccordance with one exemplary embodiment of the present invention.

FIG. 6A is a simplified block diagram of a radiator disposed in an RFlens, in accordance with one exemplary embodiment of the presentinvention.

FIG. 6B is a simplified block diagram of a radiator disposed in an RFlens, in accordance with another exemplary embodiment of the presentinvention.

FIG. 7 shows a number of electronic components of a device adapted to becharged wirelessly, in accordance with one exemplary embodiment of thepresent invention.

FIG. 8 is a schematic diagram of an RF lens wirelessly charging adevice, in accordance with one exemplary embodiment of the presentinvention.

FIG. 9 is a schematic diagram of an RF lens concurrently charging a pairof devices, in accordance with one exemplary embodiment of the presentinvention.

FIG. 10 is a schematic diagram of an RF lens concurrently charging apair of mobile devices and a stationary device, in accordance with oneexemplary embodiment of the present invention.

FIG. 11A shows computer simulations of the electromagnetic fieldprofiles of a one-dimensional RF lens, in accordance with one exemplaryembodiment of the present invention.

FIG. 11B is a simplified schematic view of an RF lens used in generatingthe electromagnetic field profiles of FIG. 11A.

FIG. 12 shows the variations in computer simulated electromagnetic fieldprofiles generated by the RF lens of FIG. 11B as a function of thespacing between each adjacent pair of radiators disposed therein.

FIG. 13A is an exemplary computer-simulated electromagnetic fieldprofile of an RF lens and using a scale of −15 dB to 0 dB, in accordancewith one exemplary embodiment of the present invention.

FIG. 13B shows the computer-simulated electromagnetic field profile ofFIG. 13A using a scale of −45 dB to 0 dB.

FIG. 14A is an exemplary computer-simulated electromagnetic fieldprofile of the RF lens of FIG. 13A and using a scale of −15 dB to 0 dB,in accordance with one exemplary embodiment of the present invention.

FIG. 14B shows the computer-simulated electromagnetic field profile ofFIG. 14A using a scale of −45 dB to 0 dB, in accordance with oneexemplary embodiment of the present invention.

FIG. 15A is an exemplary computer-simulated electromagnetic fieldprofile of an RF lens and using a scale of −15 dB to 0 dB, in accordancewith one exemplary embodiment of the present invention.

FIG. 15B shows the computer-simulated electromagnetic field profile ofFIG. 15A using a scale of −45 dB to 0 dB, in accordance with oneexemplary embodiment of the present invention.

FIG. 16A is an exemplary computer-simulated electromagnetic fieldprofile of the RF lens of FIG. 15A using a scale of −15 dB to 0 dB, inaccordance with one exemplary embodiment of the present invention.

FIG. 16B shows the computer-simulated electromagnetic field profile ofFIG. 16A using a scale of −45 dB to 0 dB, in accordance with oneexemplary embodiment of the present invention.

FIG. 17A shows an exemplary radiator tile having disposed therein fourradiators, in accordance with one exemplary embodiment of the presentinvention.

FIG. 17B shows an RF lens formed using a multitude of the radiator tilesof FIG. 17A, in accordance with one exemplary embodiment of the presentinvention.

FIG. 18 is a simplified block diagram of a radiator disposed in an RFlens, in accordance with another exemplary embodiment of the presentinvention.

FIG. 19 shows a number of electronic components disposed in a deviceadapted to be charged wirelessly, in accordance with another exemplaryembodiment of the present invention.

FIG. 20 shows an RF lens tracking a device using a signal transmitted bythe device, in accordance with another exemplary embodiment of thepresent invention.

FIG. 21A is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 21B is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 21C is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 21D is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 21E is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 21F is a simplified high-level block diagram of a device, inaccordance with one embodiment of the present invention.

FIG. 22 shows an RF lens transferring power to a device in the presenceof a multitude of scattering objects, in accordance with anotherexemplary embodiment of the present invention.

FIG. 23A shows an RF lens formed using a multitude of radiators arrangedin a circular shape, in accordance with one embodiment of the presentinvention.

FIG. 23B shows an RF lens formed using a multitude of radiators arrangedin an elliptical shape, in accordance with one embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

An RF lens, in accordance with one embodiment of the present invention,includes a multitude of radiators adapted to transmit radio frequencyelectromagnetic EM waves (hereinafter alternatively referred to as EMwaves, or waves) whose phases and amplitudes are modulated so as toconcentrate the radiated power in a small volume of space (hereinafteralternatively referred to as focus point or target zone) in order topower an electronic device positioned in that space. Accordingly, thewaves emitted by the radiators are caused to interfere constructively atthe focus point. Although the description below is provided withreference to wireless power transfer, the following embodiments of thepresent invention may be used to transfer any other kind of informationwirelessly.

FIG. 1 shows a multitude of radiators, arranged in an array 100, formingan RF lens, in accordance with one embodiment of the present invention.Array 100 is shown as including N radiators 10 ₁, 10 ₂, 10 ₃ . . . 10_(N-1), 10 _(N) each adapted to radiate an EM wave whose amplitude andphase may be independently controlled in order to cause constructiveinterference of the radiated EM waves at a focus point where a device tobe charged is located, where N is integer greater than 1. FIG. 2 is aside view of the array 100 when the relative phases of the wavesgenerated by radiators 10 _(i) (i is an integer ranging from 1 to N) areselected so as to cause constructive interference between the waves tooccur near region 102 where a device being wirelessly charged ispositioned, i.e., the focus point. Region 102 is shown as beingpositioned at approximately distance d₁ from center 104 of array 100.The distance between the array center and the focus point isalternatively referred to herein as the focal length. Although thefollowing description of an RF lens is provided with reference to a oneor two dimensional array of radiators, it is understood that an RF lensin accordance with the present invention may have any other arrangementof the radiators, such as a circular arrangement 1000 of radiators 202as shown in FIG. 22A, or the elliptical arrangement 1010 of radiators202 shown in FIG. 22B.

As seen from FIG. 2, each radiator 10, is assumed to be positioned atdistance y_(i) from center 104 of array 100. The amplitude and phase ofthe wave radiated by radiator 10 _(i) are assumed to be represented byA_(i) and θ_(i) respectively. Assume further that the wavelength of thewaves being radiated is represented by) λ. To cause the waves radiatedby the radiators to interfere constructively in region 102 (i.e., thedesired focus point), the following relationship is satisfied betweenvarious phases θ_(i) and distances y_(i):

${\theta_{1} + {\frac{2\pi}{\lambda}\sqrt{d_{1}^{2} + y_{1}^{2}}}} = {{\theta_{2} + {\frac{2\pi}{\lambda}\sqrt{d_{1}^{2} + y_{2}^{2}}}} = {\cdots = {\theta_{N} + {\frac{2\pi}{\lambda}\sqrt{d_{1}^{2} + y_{N}^{2}}}}}}$

Since the phase of an RF signal may be accurately controlled, powerradiated from multiple sources may be focused, in accordance with thepresent invention, onto a target zone where a device to be wirelesslycharged is located. Furthermore, dynamic phase control enables thetracking of the device as it moves from its initial location. Forexample, as shown in FIG. 3, if the device moves to a differentposition—along the focal plane—located at a distance d₂ from centerpoint 104 of the array, in order to ensure that the target zone is alsolocated at distance d₂, the phases of the sources may be adjusted inaccordance with the following relationship:

$\begin{matrix}{{\theta_{1} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + y_{1}^{2}}}} = {{\theta_{2} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + y_{2}^{2}}}} = {\cdots = {\theta_{N} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + y_{N}^{2}}}}}}} & (1)\end{matrix}$

Referring to FIG. 4, if the device moves to a different position awayfrom the focal plane (e.g., to a different point along the y-axis) theradiators' phases are dynamically adjusted, as described below, so as totrack and maintain the target zone focused on the device. Parametery_(c) represents the y-component of the device's new position, as shownin FIG. 4, from the focal plane of the array (i.e, the planeperpendicular to the y-axis and passing through center 104 of array100).

$\begin{matrix}{{\theta_{1} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + \left( {y_{1} - y_{c}} \right)^{2}}}} = {{\theta_{2} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + \left( {y_{2} - y_{c}} \right)^{2}}}} = {\cdots = {\theta_{N} + {\frac{2\pi}{\lambda}\sqrt{d_{2}^{2} + \left( {y_{N} - y_{c}} \right)^{2}}}}}}} & (2)\end{matrix}$

The amount of power transferred is defined by the wavelength λ of thewaves being radiated by the radiators, the array span or array apertureA as shown in FIG. 1, and the focal length, i.e. (λF/A).

In one embodiment, the distance between each pair of radiators is of theorder of the wavelength of the signal being radiated. For example, ifthe frequency of the radiated wave is 2.4 GHz (i.e., the wavelength is12.5 cm), the distance between each two radiators may be a few tenths toa few tens of the wavelengths, that may vary depending on theapplication.

An RF lens, in accordance with the present invention, is operative totransfer power wirelessly in both near-field and far field regions. Inthe optical domain, a near field region is referred to as the Fresnelregion and is defined as a region in which the focal length is of theorder of the aperture size. In the optical domain, a far field region isreferred to as the Fraunhofer region and is defined as a region in whichthe focal length (F) is substantially greater than (2 A²/λ).

To transfer power wirelessly to a device, in accordance with the presentinvention, the radiator phases are selected so as to account fordifferences in distances between the target point and the radiators. Forexample, assume that the focal length d₁ in FIG. 2 is of the order ofthe aperture size A. Therefore, since distances S₁, S₂, S₃ . . . S_(N)are different from one another, corresponding phases θ₁, θ₂, θ₃ . . .θ_(N) of radiators 10 ₁, 10 ₂, 10 ₃ . . . 10 _(N) are varied so as tosatisfy expression (1), described above. The size of the focus point(approximately λF/A) is relatively small for such regions because of thediffraction limited length.

A radiator array, in accordance with the present invention, is alsooperative to transfer power wirelessly to a target device in the farfield region where the focal length is greater than (2 A²/λ). For suchregions, the distances from the different array elements to the focusspot are assumed be to be the same. Accordingly, for such regions,S₁=S₂=S₃ . . . =S_(N), and θ₁=θ₂=θ₃ . . . =θ_(N). The size of the focuspoint is relatively larger for such regions and thus is more suitablefor wireless charging of larger appliances.

FIG. 5 shows an RF lens 200, in accordance with another embodiment ofthe present invention. RF lens 200 is shown as including a twodimensional array of radiators 202 _(i,j) arranged along rows andcolumns Although RF lens 200 is shown as including 121 radiators 202_(i,j) disposed along 11 rows and 11 columns (integers i and j areindices ranging from 1 to 11) it is understood that an RF lens inaccordance with embodiments of the present invention may have any numberof radiators disposed along U rows and V columns, where U and V areintegers greater one. In the following description, radiators 202 _(i,j)may be collectively or individually referred to as radiators 202.

As described further blow, the array radiators are locked to a referencefrequency, which may be a sub-harmonic (n=1, 2, 3 . . . ) of theradiated frequency, or at the same frequency as the radiated frequency.The phase of the wave radiated by each radiator are controlledindependently in order to enable the radiated waves to constructivelyinterfere and concentrate their power onto a target zone within anyregion in space.

FIG. 6A is a simplified block diagram of a radiator 202 disposed in RFlens 200, in accordance with one embodiment of the present invention. Asseen, radiator 202 is shown as including, in part, a programmable delayelement (also referred to herein as phase modulator) 210, aphase/frequency locked loop 212, a power amplifier 214, and an antenna216. Programmable delay element 210 is adapted to delay signal W₂ togenerate signal W₃.

The delay between signals W₂ and W₃ is determined in accordance withcontrol signal Ctrl applied to the delay element. In one embodiment,phase/frequency locked loop 212 receives signal W₁ as well as areference clock signal having a frequency F_(ref) to generate signal W₂whose frequency is locked to the reference frequency Ref. In anotherembodiment, signal W₂ generated by phase/frequency locked loop 212 has afrequency defined by a multiple of the reference frequency F_(ref).Signal W₃ is amplified by power amplifier 214 and transmitted by antenna216. Accordingly and as described above, the phase of the signalradiated by each radiator 202 may be varied by an associatedprogrammable delay element 210 disposed in the radiator.

FIG. 6B is a simplified block diagram of a radiator 202 disposed in RFlens 200, in accordance with another embodiment of the presentinvention. As seen, radiator 202 is shown as including, in part, aprogrammable delay element 210, a phase/frequency locked loop 212, apower amplifier 214, and an antenna 216. Programmable delay element 210is adapted to delay the reference clock signal F_(ref) thereby togenerate a delayed reference clock signal F_(ref) _(_) _(Delay). Thedelay between signals F_(ref) and F_(ref) _(_) _(Delay) is determined inaccordance with control signal Ctrl applied to the delay element 210.Signal W₂ generated by phase/frequency locked loop 212 has a frequencylocked to the frequency of signal F_(ref) _(_) _(Delay) or a multiple ofthe frequency of signal F_(ref) _(_) _(Delay). In other embodiments (notshown), the delay element is disposed in and is part of phase/frequencylocked loop 212. In yet other embodiments (not shown), the radiators maynot have an amplifier.

FIG. 7 shows a number of components of a device 300 adapted to becharged wirelessly, in accordance with one embodiment of the presentinvention. Device 300 is shown as including, in part, an antenna 302, arectifier 304, and a regulator 306. Antenna 302 receives theelectromagnetic waves radiated by a radiator, in accordance with thepresent invention. Rectifier 304 is adapted to convert the received ACpower to a DC power. Regulator 306 is adapted to regulate the voltagesignal received from rectifier 304 and apply the regulated voltage tothe device. High power transfer efficiency is obtained, in oneembodiment, if the aperture area of the receiver antenna is comparableto the size of the target zone of the electromagnetic field. Since mostof the radiated power is concentrated in a small volume forming thetarget zone, such a receiver antenna is thus optimized to ensure thatmost of the radiated power is utilized for charging up the device. Inone embodiment, the device may be retro-fitted externally withcomponents required for wireless charging. In another embodiment,existing circuitry present in the charging device, such as antenna,receivers, and the like, may be used to harness the power.

FIG. 8 is a schematic diagram of RF lens 200 wirelessly charging device300. In some embodiments, RF lens 200 wirelessly charges multipledevices concurrently. FIG. 9 shows RF lens 200 concurrently chargingdevices 310, and 315 using focused waves of similar or differentstrengths. FIG. 10 shows RF lens 200 wireless charging mobile devices320, 325 and stationary device 330 all of which are assumed to beindoor.

FIG. 11A shows computer-simulated electromagnetic field profilesgenerated by a one-dimensional RF lens at a distance 2 meters away fromthe RF lens having an array of 11 isotropic radiators. The beam profilesare generated for three different frequencies, namely 200 MHz(wavelength 150 cm), 800 MHz (wavelength 37.5 cm), and 2400 MHz(wavelength 12.50 cm). Since the distance between each pair of adjacentradiators of the RF lens is assumed to be 20 cm, the RF lens has anaperture of 2 m. Therefore, the wavelengths are of the order of aperturesize and focal length of the radiator. FIG. 11B is a simplifiedschematic view of such an RF lens 500 having 11 radiators 505 k that arespaced 20 cm apart from one another, where K is an integer ranging from1 to 11.

Plots 510, 520 and 530 are computer simulations of the electromagneticfield profiles respectively for 200 MHz, 800 MHz, and 2400 signalsradiated by radiator 500 when the relative phases of the variousradiators are selected so as to account for the path differences fromeach of radiators 505 _(k) to the point located 2 meters away fromradiator 505 ₆ in accordance with expression (1) above. For each ofthese profiles, the diffraction limited focus size is of the order ofthe wavelengths of the radiated signal. Plots 515, 525 and 535 arecomputer simulations of the electromagnetic field profiles at a distance2 meters away from the radiator array for 200 MHz, 800 MHz, and 2400signals respectively when the phases of radiators 505 _(k) were setequal to one another.

As seen from these profiles, for the larger wavelength having afrequency of 200 MHz (i.e, plots 510, 515), because the path differencesfrom the individual radiators to the focus point are not substantiallydifferent, the difference between profiles 510 and 515 is relativelyunpronounced. However, for each of 800 MHz and 2400 MHz frequencies, theEM confinement (focus) is substantially more when the relative phases ofthe various radiators are selected so as to account for the pathdifferences from the radiators 505 _(k) to the focus point than whenradiator phases are set equal to one another. Although the aboveexamples are provided with reference to operating frequencies of 200MHz, 800 MHz, and 2400 MHz, it is understood that the embodiments of thepresent may be used in any other operating frequency, such as 5.8 GHz,10 GHz, and 24 GHz.

FIG. 12 shows the variations in computer simulated electromagnetic fieldprofiles generated by RF lens 500—at a distance of 2 meters away fromthe RF lens—as a function of the spacing between each adjacent pair ofradiators. The RF lens is assumed to operate at a frequency of 2400 MHz.Plots 610, 620, and 630 are computer simulations of the field profilesgenerated respectively for radiator spacings of 5 cm, 10 cm, and 20 cmafter selecting the relative phases of the various radiators to accountfor the path differences from various radiators 505 _(k) to the point 2meters away from the RF lens, in accordance with expression (1) above.Plots 615, 625, and 650 are computer simulations of the field profilesgenerated respectively for radiator spacings of 5 cm, 10 cm, and 20 cmassuming all radiators disposed in RF lens 500 have equal phases. As isseen from these plots, as the distance between the radiatorsincreases—thus resulting in a larger aperture size—the EM confinementalso increases thereby resulting in a smaller focus point.

FIG. 13A is the computer simulation of the EM profile of an RF lens at adistance 3 meters away from an RF lens having disposed therein atwo-dimensional array of Hertzian dipoles operating at a frequency of900 MHz, such as RF lens 200 shown in FIG. 5. The spacing between thedipole radiators are assumed to be 30 cm. The relative phases of theradiators were selected so as to account for the path differences fromthe radiators to the focal point, assumed to be located 3 meters awayfrom the RF lens. In other words, the relative phases of the radiatorsis selected to provide the RF lens with a focal length of approximately3 meters. The scale used in generating FIG. 13A is −15 dB to 0 dB. FIG.13B shows the EM profile of FIG. 13A using a scale of −45 dB to 0 dB.

FIG. 14A is the computer simulation of the EM profile of the RF lens ofFIGS. 13A/13B at a distance 2 meters away from the focal point, i.e., 5meters away from the RF lens. As is seen from FIG. 14A, the radiatedpower is diffused over a larger area compared to those shown in FIGS.13A and 13B. The scale used in generating FIG. 14A is −15 dB to 0 dB.FIG. 14B shows the EM profile of FIG. 14A using a scale of −45 dB to 0dB.

FIG. 15A is the computer simulation of the EM profile of an RF lens at adistance 3 meters away from the RF lens having disposed therein atwo-dimensional array of Hertzian dipoles operating at a frequency of900 MHz. The spacing between the dipole radiators are assumed to be 30cm. The relative phases of the radiators are selected so as to accountfor the path differences from the radiators to the focal point, assumedto be located 3 meters away from the RF lens and at an offset of 1.5 mfrom the focal plane of the RF lens, i.e., the focus point has ay-coordinate of 1.5 meters from the focal plane (see FIG. 4). The scaleused in generating FIG. 15A is −15 dB to 0. FIG. 15B shows the EMprofile of FIG. 15A using a scale of −45 dB to 0 dB.

FIG. 16A is the computer simulation of the EM profile of the RF lens ofFIGS. 15A/15B at a distance 2 meters away from the focal point, i.e., 5meters away from the x-y plane of the RF lens. As is seen from FIG. 16A,the radiated power is diffused over a larger area compared to that shownin FIG. 15A. The scale used in generating FIG. 16A is −15 dB to 0 dB.FIG. 16B shows the EM profile of FIG. 16A using a scale of −45 dB to 0dB. The EM profiles shown in FIGS. 13A, 13B, 14A, 14B 15A, 15B, 16A, 16Bdemonstrate the versatility of an RF lens, in accordance with thepresent invention, in focusing power at any arbitrary point in 3D space.

In accordance with one aspect of the present invention, the size of thearray forming an RF lens is configurable and may be varied by usingradiator tiles each of which may include one or more radiators. FIG. 17Ashows an example of a radiator tile 700 having disposed therein fourradiators 15 ₁₁, 15 ₁₂, 15 ₂₁, and 15 ₂₂. Although radiator tile 700 isshown as including four radiators, it is understood that a radiatortile, in accordance with one aspect of the present invention, may havefewer (e.g., one) or more than (e.g., 6) four radiators. FIG. 17B shownan RF lens 800 initially formed using 7 radiator tiles, namely radiatortiles 700 ₁₁, 700 ₁₂, 700 ₁₃, 700 ₂₁, 700 ₂₂, 700 ₃₁, 700 ₃₁—each ofwhich is similar to radiator tile 700 shown in FIG. 17A—and beingprovided with two more radiator tiles 700 ₂₃ and 700 ₃₃. Although notshown, it is understood that each radiator tile includes the electricalconnections necessary to supply power to the radiators and deliverinformation from the radiators as necessary. In one embodiment, theradiators formed in the tiles are similar to radiator 202 shown in FIG.6.

In accordance with one aspect of the present invention, the RF lens isadapted to track the position of a mobile device in order to continuethe charging process as the mobile device changes position. To achievethis, in one embodiment, a subset or all of the radiators forming the RFlens include a receiver. The device being charged also includes atransmitter adapted to radiate a continuous signal during the trackingphase. By detecting the relative differences between the phases (arrivaltimes) of such a signal by at least three different receivers formed onthe RF lens, the position of the charging device is tracked.

FIG. 18 is a simplified block diagram of a radiator 902 disposed in anRF lens, such as RF lens 200 shown in FIG. 5, in accordance with oneembodiment of the present invention. Radiator 902 is similar to radiator202 shown in FIG. 6, except that radiator 902 has a receiver amplifierand phase recovery circuit 218, and a switch S₁. During power transfer,switch S₁ couples antenna 216 via node A to power amplifier 214 disposedin the transmit path. During tracking, switch S₁ couples antenna 216 vianode B to receiver amplifier and phase recovery circuit 218 disposed inthe receive path to receive the signal transmitted by the device beingcharged.

FIG. 19 shows a number of components of a device 900 adapted to becharged wirelessly, in accordance with one embodiment of the presentinvention. Device 900 is similar to device 300 shown in FIG. 7, exceptthat device 900 has a transmit amplifier 316, and a switch S₂. Duringpower transfer, switch S₂ couples antenna 302 via node D to rectifier304 disposed in receive path. During tracking, switch S₂ couples antenna302 via node C to transmit amplifier 316 to enable the transmission of asignal subsequently used by the RF lens to detect the position of device300. FIG. 20 shows RF lens 200 tracking device 900 by receiving thesignal transmitted by device 900.

A radiator, in accordance with any of the embodiments of the presentinvention, in addition to transferring RF power to a device wirelessly,may also wirelessly transfer modulated data to such a device. Forexample, a radiator, in accordance with the embodiments of the presentinvention, may operate as a wireless local area network (WLAN) router todirect signal power toward other such routers or receivers (WLAN orotherwise) to increase the received signal power by orders of magnitudeand thereby increase the range, coverage and wireless data rates, aswell as reduce the effect of multi-path propagation of the RF signal andpower. Transferring wireless signal and/or power, in accordance withembodiments of the present invention and in conformity with anycommunication standards, such as WiFi, Zigbee, Bluetooth, GSM, GPRS,Edge, and UMTS, to a receiving device, and tracking the location of thedevice as it moves through physical space, greatly increases the rangeof the data link and achievable data rates.

Because the power levels required for data transmission are typicallyorders of magnitude lower than the power levels for wireless powertransfer, in accordance with embodiments of the present invention, bothpower and data transmission may be performed concurrently. In otherwords, for any given amount of emitted power by a generation unit, inaccordance with embodiments of the present invention, the range ofwireless power transfer is smaller than the range for wireless datatransmission. Therefore, a device that is in range for wireless powertransfer, is also in range for wireless data transmission. Furthermore,the amount of power siphoned off in detecting the transmitted datasignal is typically much smaller compared to the power available forconcurrently powering the device. In addition, a device that may becharged wirelessly can also operate over the relatively narrow range offrequencies around the center frequency spanned by most signalmodulation schemes used in data transmission.

FIG. 21A is a simplified high-level block diagram of a device 750 (e.g.,cellular phone, camera, wearable device, toy), in accordance with oneembodiment of the present invention. Device 750 is shown as including,in part, an antenna 760, a directional power splitter/coupler(alternatively referred to herein as coupler) 752, a power recovery unit754, and a radio signal receiver/demodulator (alternatively referred toherein as receiver) 756. Antenna 760 is adapted to receive a signal froma radiator or an array of radiators, as described for example above, anddeliver the received signal to coupler 752. The signal received by theantenna is a modulated signal that carries information/data as well asRF power, both of which are transmitted using the same frequency.Coupler 752 is adapted to transfer a first portion of the received RFsignal to receiver 756 and a second portion of the received signal topower recovery unit 754. Receiver 756 demodulates the received signal torecover the transmitted data. Power recovery unit 754 is adapted toconvert the received RF signal to a DC power to power device 750 orcharge device 750's battery. Although not shown, it is understood thatdevice 750 may use filters and/or transistors instead of coupler 752 todistribute the received RF power between power recovery unit 754 andreceiver 756. U.S. application Ser. No. 14/552,249, filed Nov. 24, 2014,entitled “Active CMOS Recovery Units For Wireless Power Transmission”,the content of which is incorporated herein by reference in itsentirety, describes in detail various embodiments of power recovery unit754. In one embodiment, directional coupler/splitter 752 is adjustable(via a controller not shown in FIG. 21A) that can vary the split ratioso as to change the amount of power coupler/splitter 752 provides toreceiver 756 relative to the power it provides to power recovery unit754.

FIG. 21B is a simplified high-level block diagram of a device 755, inaccordance with one embodiment of the present invention. Device 750 isshown as including, in part, an antenna 760, a controller 762, a powerrecovery unit 754, and a radio signal receiver/demodulator (hereinafterreceiver) 756. Antenna 760 is adapted to receive a signal from aradiator or an array of radiators, as described above, and deliver thereceived signal to controller 762. Controller 762 is adapted todistribute the received RF power in accordance with an inverse ratio ofthe impedances of receiver 756 and power recovery unit 754. Controller762 may be further adapted to vary the impedances seen at its outputterminals such that the output impedance having a closer value to theimpedance seen at the input of controller 762 receives a higher amountof the received RF power.

FIG. 21C is a simplified high-level block diagram of a device 760, inaccordance with another embodiment of the present invention. Device 760is similar to device 750 except that device 760 uses a switch 764 inplace of coupler 752. When switch 764 is in position P₁, all of thereceived RF power is delivered to power recovery unit 754 thereby tocharge device 760. When switch 764 is in position P₂, all of thereceived RF power is delivered to receiver 756 to receive thetransmitted data. For example, if device 760 is determined as beingout-of-range for wireless power charging, switch 764 is placed inposition P₂ to supply all of the received wireless power to receiver 756to improve, e.g., its signal to noise ratio. Likewise, if device 760 isdetected as being within range but requiring no additional charge,switch 764 is placed in position P₂ to supply all of the receivedwireless power to receiver 756. If, for example, data reception is notof interest, switch 764 is placed in position P₁ to supply all of thereceived RF power to power recovery unit 754.

For example, assume that an RF lens or a radiator array (a powergenerating unit) broadcasts an RF signal to determine if the received RFsignal is strong enough to wirelessly charge a device receiving the RFsignal. If the received RF signal is detected as not being strong enoughto wirelessly charge the device, a controller (not shown in FIG. 21C)controlling switch 764 may switch to radio receiving mode by placingswitch 764 to position P₂. Once in the radio receiving mode, the devicemay then communicate with the radiator array to enable the radiatorarray to focus its RF power on the device. After the radiator arrayfocuses its transmitted RF signal on device 760, thereby causing thereceived RF signal to be sufficient for wireless charging, thecontroller may place switch 764 in position P₁ to enable power recoveryunit 754 to charge device 760. When device 760 is charged to asufficient level, it may so inform the controller thus causing switch764 to be placed in switch position P₂. It is understood that any numberof conditions and criteria may be used to change the position of switch764.

FIG. 21D is a simplified high-level block diagram of a device 765, inaccordance with another embodiment of the present invention. Device 765is shown as including, in part, an antenna 760, a coupler 752, a switch764, a power combiner 758, a power recovery unit 754, and a receiver756. Antenna 760 is adapted to receive a modulated signal that carriesinformation as well as RF power, both of which are transmitted using thesame frequency. Coupler 752 is adapted to transfer a first portion ofthe received RF signal to power combiner 758, and a second portion ofthe received signal to switch 764. When switch 764 is position P₁, (i)the first portion of the power supplied by coupler 752 is delivered toreceiver 756 via power combiner 758, and (ii) the second portion of thepower supplied by coupler 752 is delivered to power recovery unit 754 towirelessly charge device 765. Receiver 756 demodulates the receivedsignal to recover the transmitted data.

When switch 764 is position P₂, power combiner 758 combines the firstportion of the power it receives from coupler 752 with the secondportion of power it receives from switch 764 and delivers the combinedpower to receiver 756. Accordingly, in such embodiments, receiver 756continues to receive the transmitted RF signal regardless of the switchposition. For example, when the received RF power is detected as beingbelow a threshold value, switch 764 is placed in position P₂ (via acontroller not shown) so that all the received RF power is used forsignal reception. When the received RF power is detected as being abovea threshold value and/or device 765 requests to be charged, switch 764is placed in position P₁ (via the controller) so that a relatively smallfraction of the received RF power is used for signal detection byreceiver 756, and the remainder of the RF power is used by powerrecovery unit 754 to charge device 765.

FIG. 21E is a simplified high-level block diagram of a device 775, inaccordance with another embodiment of the present invention. Device 775is shown as including, in part, an antenna 760, a coupler 752, a switch764, a power combiner 758, a power recovery unit 754, and a receiver756. Antenna 760 is adapted to receive a modulated signal that carriesinformation/data as well as RF power, both of which are transmittedusing the same frequency. Receiver 756 demodulates the received signalto recover the transmitted data.

When switch 764 is position P₂, the received RF signal is supplied todirectional coupler 752, which in turn, delivers (i) a first portion ofthe received power to receiver 756 via power combiner 758, and (ii) asecond portion of the received power to power recovery unit 754 forwirelessly charging device 775. When switch 764 is in position P₁,substantially all of the received RF power is delivered to receiver 756via power combiner 758. Accordingly, device 775 is adapted tocontinuously deliver the RF signal to receiver 756.

FIG. 21F is a simplified high-level block diagram of a device 785, inaccordance with another embodiment of the present invention. Device 785is shown as including, in part, an antenna 760, an adjustable powersplitter/coupler 782, a control unit 762, a power recovery unit 754, anda receiver 756. Antenna 760 is adapted to receive a modulated signalthat carries information as well as RF power, both of which aretransmitted using the same frequency. Adjustable power splitter/coupler782 is adapted to split the RF signal it receives from antenna 760 intofirst and second portions in accordance with a split ratio adjustablepower splitter/coupler 782 receives from control unit 762. The splitratio supplied by control unit 762 may be defined by any number offactors, such as the target date rate set by receiver 756, the DC powerrequested by the power recovery unit 754, the power requested byreceiver 756, and the like.

Referring to FIGS. 21A-21E, it is understood that power combiner 758 maybe formed using any arrangement or configuration of active and/orpassive devices capable of combining power from two or more sources.Typical examples include lossless power combiners such as coupledtransmission lines, their lumped circuit equivalent using capacitors orinductors, magnetic transformers, and other circuits, as is well known.Directional coupler 752 may include coupled transmission lines,transformers and/or their lumped circuit equivalent. Switch 764 adaptedto switch RF power may include pass gates, electronically tunableimpedance networks, relays and the like, as is also well known.

In accordance with another embodiment of the present invention, a pulsebased measurement technique is used to track the position of the mobiledevice. To achieve this, one or more radiators forming the RF lenstransmit a pulse during the tracking phase. Upon receiving the pulse,the device being tracked sends a response which is received by theradiators disposed in the array. The travel time of the pulse from theRF lens to the device being tracked together with the travel times ofthe response pulse from the device being tracked to the RF lens isrepresentative of the position of the device being tracked. In thepresence of scatterers, the position of the device could be trackedusing such estimation algorithms as maximum likelihood, or least-square,Kalman filtering, a combination of these techniques, or the like. Theposition of the device may also be determined and tracked using WiFi andGPS signals.

The presence of scattering objects, reflectors and absorbers may affectthe RF lens' ability to focus the beam efficiently on the deviceundergoing wireless charging. For example, FIG. 22 shows an RF lens 950transferring power to device 300 in the presence of a multitude ofscattering objects 250. To minimize such effects, the amplitude andphase of the individual radiators of the array may be varied to increasepower transfer efficiency. Any one of a number of techniques may be usedto vary the amplitude or phase of the individual radiators.

In accordance with one such technique, to minimize the effect ofscattering, a signal is transmitted by one or more of the radiatorsdisposed in the RF lens. The signal(s) radiated from the RF lens isscattered by the scattering objects and received by the radiators (seeFIG. 18). An inverse scattering algorithm is then used to construct thescattering behavior of the environment. Such a construction may beperformed periodically to account for any changes that may occur withtime. In accordance with another technique, a portion or the entireradiator array may be used to electronically beam-scan the surroundingsto construct the scattering behavior from the received waves. Inaccordance with yet another technique, the device undergoing wirelesscharging is adapted to periodically send information about the power itreceives to the radiator. An optimization algorithm then uses thereceived information to account for scattering so as to maximize thepower transfer efficiency.

In some embodiments, the amplitude/phase of the radiators or theorientation of the RF lens may be adjusted to take advantage of thescattering media. This enable the scattering objects to have the properphase, amplitude and polarization in order to be used as secondarysources of radiation directing their power towards the device toincrease the power transfer efficiency.

The above embodiments of the present invention are illustrative and notlimitative. Embodiments of the present invention are not limited bynumber of radiators disposed in an RF lens, nor are they limited by thenumber of dimensions of an array used in forming the RF lens.Embodiments of the present invention are not limited by the type ofradiator, its frequency of operation, and the like. Embodiments of thepresent invention are not limited by the type of device that may bewirelessly charged. Embodiments of the present invention are not limitedby the type of substrate, semiconductor, flexible or otherwise, in whichvarious components of the radiator may be formed. Other additions,subtractions or modifications are obvious in view of the presentdisclosure and are intended to fall within the scope of the appendedclaims.

What is claimed is:
 1. A device comprising: an antenna adapted toreceive an RF signal comprising modulated data; a splitter/couplercoupled to the antenna and adapted to split the received RF signal intofirst and second portions; a receiver adapted to demodulate the datafrom the first portion of the RF signal; and a power recovery unitadapted to convert the second portion of the RF signal to a DC power topower the device.
 2. A device comprising: an antenna adapted to receivean RF signal comprising modulated data; a receiver adapted to demodulatethe data from a first portion of the RF signal; a power recovery unitadapted to convert a second portion of the RF signal to a DC power topower the device; and a controller adapted to receive the RF signal fromthe antenna and generate the first and second portions of the RF signalin accordance with impedance values of the receiver and the powerrecovery unit.
 3. A device comprising: an antenna adapted to receive anRF signal comprising modulated data; a switch adapted to receive the RFsignal from the antenna; a power recovery unit adapted to convert the RFsignal to a DC power to power the device when the switch is in a firstposition; and a receiver adapted to demodulate the data from thereceived RF signal when the switch is in a second position.
 4. A devicecomprising: an antenna adapted to receive an RF signal comprisingmodulated data; a splitter/coupler coupled to the antenna and adapted tosplit the received RF signal into first and second portions; a switchadapted to receive the second portion of the RF signal from thesplitter/coupler; a power recovery unit adapted to convert the secondportion of the RF signal to a DC power to power the device when theswitch is in a first position; and a power combiner adapted to receivethe first portion of the RF signal from the splitter/coupler and furtherto receive the second portion of the RF signal when the switch is in asecond position; and a receiver adapted to demodulate the data from anoutput signal of the power combiner.
 5. A device comprising: an antennaadapted to receive an RF signal comprising modulated data; a switchcoupled to the antenna to receive the RF signal therefrom; a powercombiner coupled to a first output terminal of the switch to receive theRF signal when the switch is in a first position; a splitter/couplercoupled to a second output terminal of the switch to receive the RFsignal when the switch is in a second position, said splitter adapted tosplit the RF signal into a first portion and a second portion, saidsplitter/coupler delivering the first portion of the RF signal to thepower combiner; a power recovery unit adapted to convert the secondportion of the RF signal to a DC power to charge the device when theswitch is in the second position; a receiver adapted to demodulate thedata from an output signal of the power combiner.
 6. The device of claim5 further comprising: a controller adapted to cause the switch to be inthe first position when a power of the received RF signal is less than athreshold value.
 7. The device of claim 5 further comprising: acontroller adapted to cause the switch to be in the first position whenthe device indicates that its DC power exceeds a threshold value.
 8. Thedevice of claim 4 further comprising: a controller adapted to cause theswitch to be in the first position when a power of the received RFsignal is less than a first threshold value.
 9. The device of claim 4further comprising: a controller adapted to cause the switch to be inthe first position when the device indicates that its DC power exceeds asecond threshold value.
 10. A method comprising: receiving an RF signalcomprising modulated data; splitting the received RF signal into firstand second portions; demodulating the data from the first portion of theRF signal; and converting the second portion of the RF signal to a DCpower.
 11. A method comprising: receiving an RF signal comprisingmodulated data; demodulating the data from a first portion of thereceived RF signal via a receiver; converting a second portion of the RFsignal to a DC power via a power recovery unit; generating the first andsecond portions of the RF signal in accordance with impedance values ofthe receiver and the power recovery unit
 12. A method comprising:receiving an RF signal comprising modulated data; converting the RFsignal to a DC power when a switch is in a first position; anddemodulating the data from the received RF signal when the switch is ina second position.
 13. A method comprising: receiving an RF signalcomprising modulated data; demodulating the data using either a firstportion of the received RF signal or the received RF signal; andconverting a second portion of the RF signal to a DC power when thefirst portion of the RF signal is used for demodulating the data. 14.The method of claim 13 further comprising: demodulating the data usingthe received RF signal when a power of the received RF signal is lessthan a first threshold value.
 15. The method of claim 14 furthercomprising: demodulating the data using the received RF signal when anindication is received that a battery charge exceeds a threshold value.16. A device comprising: an antenna adapted to receive an RF signalcomprising modulated data; a controller; an adjustable splitter/coupleradapted to split the received RF signal into first and second portionsin accordance with a value said adjustable splitter/coupler receivesfrom the controller; a receiver adapted to demodulate the data from thefirst portion of the RF signal; and a power recovery unit adapted toconvert the second portion of the RF signal to a DC power to power thedevice.
 17. The device of claim 16 wherein said value is defined by atarget data rate.
 18. The device of claim 16 wherein said value isdefined by a DC power requirement of the device.
 19. A methodcomprising: receiving an RF signal; splitting the received RF signalinto first and second portions in accordance with a received value;demodulating the data from the first portion of the RF signal; andconverting the second portion of the RF signal to a DC power.
 20. Themethod of claim 19 wherein said value is defined by a target data rate.21. The device of claim 16 wherein said value is defined by a DC powerrequirement.
 22. The device of claim 1 wherein said splitter/coupler isan adjustable splitter/coupler.